Modular proximal body trial

ABSTRACT

A trial system for determining a suitable proximal body implant for hip replacement surgery comprises a separator instrument, a trial body attachable to a distal stem, and an insert. The insert is positioned within the trial body to receive the separator instrument. As the separator instrument is rotated about its axis, a ramp element of the insert guides a pin of the separator instrument, so as to separate the trial body from the distal stem. Additional apparatus, methods, and systems are disclosed.

RELATED APPLICATIONS

This applications claims the benefit of priority to U.S. ProvisionalApplication Ser. No. 62/088,874, filed Dec. 8, 2014, the content ofwhich is hereby incorporated by reference in its entirety.

BACKGROUND

A human hip joint connects a femur (sometimes referred to as a thighbone) to an acetabulum (sometimes referred to as a hip socket) of thepelvis. Hip joints support the weight of a human body, and are importantfor maintaining balance.

Some types of injury, disease, or degeneration can produce pain,restricted motion in the hip joint, or both. One treatment for certaintypes of damage to a hip joint is surgery. In some cases, the hip jointis surgically replaced.

OVERVIEW

To better illustrate the trial system disclosed herein, a non-limitinglist of examples is provided here:

In Example 1, a trial system for determining a suitable proximal bodyimplant for hip replacement surgery can be provided that includes aseparator instrument, a trial body attachable to a distal stem, and aninsert positioned within the trial body, wherein the insert includes afirst ramp element configured to receive the separator instrument suchthat as the separator instrument is rotated about its axis, the firstramp element guides a first pin of the separator instrument so as toseparate the trial body from the distal stem.

In Example 2, the trial system of Example 1 is optionally configuredsuch that a distal end of the separator instrument is configured tocontact a proximal end of the distal stem, such that the first rampelement facilitates separation forces between the distal end of theseparator instrument and the proximal end of the distal stem.

In Example 3, the trial system of any one of or any combination ofExamples 1-2 is optionally configured such that the insert is weldedwithin the trial body.

In Example 4, the trial system of any one of or any combination ofExamples 1-2 is optionally configured such that the insert is integralwith the trial body.

In Example 5, the trial system of any one of or any combination ofExamples 1-4 is optionally configured such that the distal stemcomprises a distal stem trial.

In Example 6, the trial system of any one of or any combination ofExamples 1-5 is optionally configured such that the first pin extendsalong an axis that is nonparallel to the axis of the separatorinstrument.

In Example 7, the trial system of any one of or any combination ofExamples 1-6 is optionally configured such that the insert includes asecond ramp element configured to guide a second pin of the separatorinstrument to facilitate separating the trial body from the distal stem.

In Example 8, the trial system of any one of or any combination ofExamples 1-7 is optionally configured such that the trial body isattachable to the distal stem via a taper lock.

In Example 9, the trial system of any one of or any combination ofExamples 1-8 is optionally configured such that the insert includes afirst slot configured to receive the first pin and guide the first pinto the first ramp element.

In Example 10, the trial system of any one of or any combination ofExamples 1-9 is optionally configured such that the trial body isconfigured to pass over a guide rod of the distal stem.

In Example 11, the trial system of any one of or any combination ofExamples 1-10 is optionally configured such that the insert includes aninterior passage that allows the separator instrument to pass throughthe insert.

In Example 12, a trial system for determining a suitable proximal bodyimplant for hip replacement surgery can be provided that includes aseparator instrument and a plurality of trial bodies, wherein theseparator instrument includes a first pin, wherein each trial body ofthe plurality of trial bodies includes a distal portion attachable to adistal stem, a proximal portion extending from and nonparallel to thedistal portion, and an insert positioned within the distal portion ofthe trial body, wherein the insert includes a first ramp elementconfigured to engage the first pin of the separator instrument such thatthe first pin traverses the first ramp element in response to rotationof the separator instrument about its axis, thereby allowing separationof the trial body from the distal stem.

In Example 13, the trial system of Example 12 is optionally configuredsuch that the separator instrument includes a second pin extending fromand nonparallel to the separator instrument.

In Example 14, the trial system of Example 13 is optionally configuredsuch that the insert includes a second ramp element configured to engagethe second pin of the separator instrument such that the second pintraverses the ramp element in response to rotation of the separatorinstrument about its axis.

In Example 15, a method can be provided that includes inserting aseparator instrument into an insert of a trial body attached to a distalstem, and rotating the separator instrument about its axis, such thatone or more pins of the separator instrument traverse one or more rampsof the insert, creating a separation force between the trial body andthe distal stem.

In Example 16, the method of Example 15 optionally includes attachingthe trial body to the distal stem via a taper lock.

In Example 17, the method of any one of or any combination of Examples15 and 16 optionally includes separating the trial body from the distalstem.

In Example 18, the method of any one of or any combination of Examples15-17 optionally includes inserting the separator instrument into theinsert of the trial body by inserting the one or more pins of theseparator instrument into one or more slots of the insert, wherein theone or more slots guide the one or more pins of the separator instrumentto the one or more ramps.

In Example 19, the method of any one of or any combination of Examples15-18 optionally includes passing the trial body over a guide rod thatguides the trial body onto the distal stem.

In Example 20, the method of any one of or any combination of Examples15-19 optionally includes determining a suitable proximal body implantfor hip replacement surgery based on the trial body.

In Example 21, the trial system or method of any one of or anycombination of Examples 1-20 is optionally configured such that allelements or options recited are available to use or select from.

These and other examples and features of the present devices, systems,and methods will be set forth in part in the following DetailedDescription. This overview is intended to provide a summary of subjectmatter of the present patent application. It is not intended to providean exclusive or exhaustive removal of the invention. The detaileddescription is included to provide further information about the presentpatent application.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, which are not necessarily drawn to scale, like numeralsmay describe similar components in different views. Like numerals havingdifferent letter suffixes may represent different instances of similarcomponents. The drawings illustrate generally, by way of example, butnot by way of limitation, various embodiments discussed in the presentdocument.

FIG. 1 is an exploded perspective view of a modular proximal body trialsystem, in accordance with at least one example of the presentdisclosure.

FIG. 2 is a cross-section view of a modular proximal body trial system,in accordance with at least one example of the present disclosure.

FIG. 3 is a partial cross-section view of a modular proximal body trialsystem before a separator instrument is inserted into a trial body, inaccordance with at least one example of the present disclosure.

FIG. 4 is a partial cross-section view of a modular proximal body trialsystem with a separator instrument inserted in a first position, inaccordance with at least one example of the present disclosure.

FIG. 5 is a partial cross-section view of the modular proximal bodytrial system of FIG. 4 after the separator instrument has been rotatedabout its axis, in accordance with at least one example of the presentdisclosure.

FIG. 6 is a flow chart of an example method of using the modularproximal body trial system of FIGS. 1-5, in accordance with at least oneexample of the present disclosure.

DETAILED DESCRIPTION

Hip replacement surgery (hip arthroplasty) can include implantation of adistal stem into a femur of a patient, and implantation of a proximalbody to connect to the distal stem. Implantable proximal bodies can bepresented to a practitioner in the form of a set. The implantableproximal bodies in the set can include discrete combinations of theparameters of height (i.e., the length of the femur) and offset (i.e.,the lateral distance from the central axis of the femur to the center ofthe femoral head in the acetabulum). Height and offset are establishedquantities in the field of hip replacement surgery.

In order to determine the most appropriate height and offset for aparticular patient, a practitioner can use a “trial” or “provisional,”which is shaped and sized similar to the implantable components, but isremovable and can be reused or disposed of A practitioner can tryvarious sizes by temporarily attaching the trial to a stem, and notingthe fit of the trial with the anatomy of the patient. Once a best fit isfound, the practitioner can note the values of height and offset of thetrial that provides the best fit. The practitioner can then remove thetrial, select an implantable proximal body from the set (the selectedbody having height and offset values that are closest to the notedvalues) and implant the selected implantable proximal body.

FIG. 1 is an exploded perspective view of a modular proximal body trialsystem 100, in accordance with at least one example of the presentdisclosure. The trial system 100 can comprise a separator instrument102, a trial body 104, and an insert 106. A distal portion 108 of thetrial body 104 is attachable to a proximal end of a distal stem. In atleast one example, the distal stem can comprise a distal stem trial. Inanother example, the distal stem can comprise a distal stem implant. Inat least one example, the distal portion 108 can be substantiallycylindrical in shape, with a longitudinal axis 130 extending verticallyfrom the proximal direction to the distal direction. In at least oneexample, the proximal end of the distal stem can extend into the distalportion 108 of the trial body 104. In some examples, the distal portion108 can be dimensioned such that the trial body 104 can fit snugly, butremovably, over the proximal end of the distal stem. In at least oneexample, the distal portion 108 of the trial body 104 can be coupled tothe proximal end of the distal stem using one or more taper locks. Somedistal stems can comprise a guide rod that attaches to a hole in aproximal portion of the distal stem to aid insertion into the femoralcanal, guide the proximal reamer over the distal stem, and guide theproximal body trial or implant onto the distal stem. In at least oneexample, the distal portion 108 of the trial body 104 can be configuredto pass over a guide rod of the distal stem.

The trial system 100 can further comprise a proximal portion 110. Insome examples, the proximal portion 110 can extend from the distalportion 108. In at least one example, the proximal portion 110 can benonparallel relative to the distal portion 108. The angle of theproximal portion 110 relative to the distal portion 108 can differ invarious examples of the trial body 104. Various examples of the trialbody 104 can comprise different combinations of height and offset. In atleast one example, the trial system 100 can comprise a plurality oftrial bodies 104 representing different parameters for height, offset,angle (of the proximal portion 110 relative to the distal portion 108),or a combination of these.

The separator instrument 102 can comprise one or more pins 112, 114. Forexample, in at least one example, the separator instrument 102 cancomprise two pins 112, 114. Other examples of the separator instrument102 can comprise more than two pins, or less than two pins. The pins112, 114 can extend along an axis 132 that is nonparallel to the axis130 of the separator instrument 102. In at least one example, the pins112, 114 can be integral with the separator instrument 102. In anotherexample, the pins 112, 114 can be formed on, or otherwise attached tothe separator instrument 102. The separator instrument 102 can begenerally shaped and dimensioned such that at least a distal end 116 ofthe separator instrument 102 passes through or fits within an interiorpassage 118 of the insert 106. The distal end 116 of the separatorinstrument 102 can be further configured to contact a proximal end ofthe distal stem.

The insert 106 can be positioned within an interior 120 of the trialbody 104. In at least one example, the insert 106 can be coupled to theinterior 120 of the trial body 104 via, for example, at least one of: aweld, adhesive, a cross pin, a friction fit, a combination of these, orthe like. In at least one example, the insert 106 can be integral withthe trial body 104. The insert 106 can comprise one or more rampelements 122, 124. For example, in the illustrated example, the insert106 can comprise two ramp elements 122, 124. Other examples of theinsert 106 can comprise more than two ramp elements, or less than tworamp elements. In some examples, the number of ramp elements 122, 124 ofthe insert 106 can be coordinated with the number of pins 112, 114 ofthe separator instrument 102. In some examples, the insert 106 cancomprise one or more slots 126, 128 configured to receive pins 112, 114of the separator instrument 102 and guide the pins 112, 114 to rampelements 122, 124 of the insert 106. In at least one example, the numberof slots 126, 128 can be coordinated with the number of pins 112, 114 ofthe separator instrument 102. For example, in the illustrated example,the insert 106 can comprise two slots 126, 128 to coordinate with thetwo pins 112, 114 of the separator instrument 102, 104. Other examplesof the insert 106 can comprise more than two slots or less than twoslots.

The ramp elements 122, 124 of the insert 106 can be configured toreceive the pins 112, 114 of the separator instrument 102 and guide thepins 112, 114 as the separator instrument 102 is rotated about its axis130. As the separator instrument 102 is rotated about its axis 130, thepins 112, 114 can traverse the ramp elements, creating separation forces(e.g., normal forces) between the distal end 116 of the separatorinstrument 102 and the proximal end of the distal stem. That is, theramp elements 122, 124 of the insert 106, in combination with the pins112, 114 of the separator instrument 102, can facilitate separation ofthe trial body 104 from the distal stem. In at least one example, theseparation forces created by the pins 112, 114 traversing the rampelements 122, 124 can be sufficient to disengage a taper lock thatcouples the trial body 104 to the distal stem.

The direction of rotation necessary to decouple the trial body 104 fromthe distal stem can depend on the orientation of the ramp elements 122,124. For example, in some examples, the ramp elements 122, 124 areoriented such that a clockwise rotation of the separator instrument 102creates the separation forces, while in other examples, the rampelements 122, 124 are oriented such that a counterclockwise rotation ofthe separator instrument 102 creates the separation forces. In at leastone example, the ramp elements 122, 124 can be oriented such that eithera clockwise or a counterclockwise rotation will create the separationforces. Further, various examples may employ different configurations ofthe ramp elements 122, 124 to affect the degree of rotation of theseparator instrument 102 necessary to separate the trial body 104 fromthe distal stem. In at least one example, the separator instrument 102can rotate about its axis (130) 270° or less to decouple the trial body104 from the distal stem. In some examples, the separator instrument 102can rotate about its axis (130) 90° to decouple the trial body 104 fromthe distal stem.

FIG. 2 is a cross-section view of the modular proximal body trial system100, in accordance with at least one example of the present disclosure.In the illustrated example, the trial system 100 comprises the trialbody 104 and insert 106 discussed above with regard to FIG. 1, alongwith a distal stem 202. As shown, the distal portion 108 of the trialbody 104 can be fitted over the distal stem 202. In at least oneexample, the trial body 104 can be coupled to the distal stem 202 via ataper lock. As further illustrated in FIG. 2, the insert 106 can bepositioned within the trial body 104, such that the separator instrument102 (FIG. 1) can pass through an interior passage 118 of the insert 106until a proximal end 204 of the distal stem 202 contacts or ispositioned adjacent to the distal end 116 of the separator instrument102. The slots 126, 128 can guide the pins 112, 114 (FIG. 1) of theseparator instrument 102 to the corresponding ramp elements 122, 124(FIG. 1) of the insert 106. Each of the trial body 104, insert 106, andseparator instrument 102 can comprise any of a variety of materials. Inat least one example, one or more of the trial body 104, insert 106, andseparator instrument 102 comprises metal, for example, stainless steel.In some examples, one or more of the trial body 104, insert 106, andseparator instrument 102 comprises a combination of materials.

FIG. 3 is a partial cross-section view of the modular proximal bodytrial system 100 before the separator instrument 102 is inserted intothe trial body 104, in accordance with at least one example of thepresent disclosure. As shown in FIG. 3, the distal portion 108 of thetrial body 104 is coupled to the distal stem 202, and the insert 106 ispositioned within the trial body 104. Prior to a separation procedure,the separator instrument 102 can be aligned with the insert 106, suchthat the slots 126, 128 of the insert 106 receive the pins 112, 114 ofthe separator instrument 102 when the separator instrument 102 isinserted into the interior passage 118 of the insert 106.

FIG. 4 is a partial cross-section view of the modular proximal bodytrial system 100 with the separator instrument 102 inserted in a firstposition, in accordance with at least one example of the presentdisclosure. As shown in FIG. 4, the distal portion 108 of the trial body104 is coupled to the distal stem 202, for example, via a taper lock. Inthe illustrated example, the separator instrument 102 has been insertedinto the interior passage 118 (FIGS. 1-3) of the insert 106, such thatthe slot 126 has guided the pin 112 to the ramp element 122. Althoughnot shown, the slot 128 has guided the pin 114 to the ramp element 124.In the illustrated example, the separator instrument 102 has not yetbeen rotated about its axis 130 to traverse the ramp element 122 (andthe ramp element 124). As such, the distal end 116 of the separatorinstrument 102 is in contact with the proximal end 204 of the distalstem 202, but has not yet separated the trial body 104 from the distalstem 202.

FIG. 5 is a partial cross-section view of the modular proximal bodytrial system 100, assembled as shown in FIG. 4, after the separatorinstrument 102 has been rotated about its axis 130, in accordance withat least one example of the present disclosure. As the separatorinstrument 102 rotates from its position in FIG. 4 to its position inFIG. 5, the pin 112 travels along the ramp element 122 (and the pin 114travels along the ramp 124), such that the slope of the ramp element andthe contact between the separator instrument 102 and the proximal end204 of the distal stem 202 create a separation force that forces thetrial body 104 away from the distal stem 202. The separator instrument102 travels distally in relation to the trial body 104 as the separatorinstrument 102 rotates about its axis 130, until the separating forcecauses the trial body 104 to separate from the distal stem 202. Theinsert 106 remains positioned within the trial body 104 as the trialbody 104 is removed from the distal stem 202.

In the illustrated example, the separator instrument 102 has beenrotated about its axis 130 in a counterclockwise direction less than180° to decouple the trial body 104 from the distal stem 202. However,in other examples, the insert 106 may be configured, such that theseparator instrument 102 rotates in a clockwise direction to decouplethe trial body 104 from the distal stem 202. Further, the degree ofrotation of the separator instrument 102 that results in separation ofthe trial body 104 from the distal stem 202 may vary with otherexamples. In at least one example, the separator instrument 102 isremoved from the insert 106 by reversing the motions of insertion. Forexample, in the illustrated example, the separator instrument 102 isremoved by a practitioner rotating the separator instrument 102 aboutits axis 130 in the clockwise direction until the pin 112 is alignedwith the slot 126, and then pulling the separator instrument 102 throughthe slot 126.

FIG. 6 is a flow chart of a method 600 of determining a suitableproximal body implant for hip replacement surgery, in accordance with atleast one example of the present disclosure. As a matter of convenience,the method 600 is described with reference to the trial system 100 ofFIGS. 1-5. At block 602, a user can select a trial body 104. Forexample, in at least one example, the user can select a trial body 104from a plurality of trial bodies representing different parameters, suchas height, offset, angle (of a proximal portion 110 of the trial bodyrelative to a distal portion 108 of the trial body), or a combination ofthese.

At block 604, the user can attach the trial body 104 to the distal stem202. The distal stem 202 may be a distal stem trial or a distal stemimplant. In at least one example, the user can couple the trial body 104to the distal stem 202 via one or more taper locks. In at least oneexample, the trial body 104 can pass over a guide rod that guides thetrial body 104 onto the distal stem 202. The user can then judge theappropriateness of the parameters of the trial body 104. If theparameters of the trial body 104 are appropriate, the trial body 104 canbe removed in preparation for the associated implant. If the parametersof the trial body 104 are not appropriate, the trial body 104 can beremoved to attempt a different one of the plurality of trial bodiescomprising different parameters.

At block 606, the user can insert the separator instrument 102 into thetrial body 104 by directing the separator instrument 102 toward thedistal stem 202. In at least one example, the user can align the one ormore pins 112, 114 of the separator instrument 102 with one or moreslots 126, 128 of the insert 106 positioned within the trial body 104.At block 608, the user can engage the insert 106 with the one or morepins 112, 114 of the separator instrument 102. The separator instrument102 can then pass through the interior passage 118 of the insert 106 asthe one or more slots 126, 128 of the insert receive the one or morepins 112, 114 of the separator instrument 102. The one or more slots126, 128 can be configured to guide the one or more pins 112, 114 to oneor more corresponding ramp elements 122, 124 of the insert 106.

At block 610, the user can rotate the separator instrument 102 about itsaxis 130, such that the one or more pins 112, 114 of the separatorinstrument 102 traverse the one or more ramp elements 122, 124 of theinsert 106. The one or more pins 112, 114 traversing the one or moreramp elements 122, 124 can create a separation force between the distalend 116 of the separator instrument 102 and the proximal end 204 of thedistal stem 202. The separation force causes the trial body 104 todecouple from the distal stem 202. For example, in at least one example,the separation force (e.g., a normal force) disengages a taper lock. Theinsert 106 may be configured such that the one or more pins 112, 114traverse the one or more ramp elements 122, 124 when the separatorinstrument 102 rotates either clockwise or counterclockwise.

At block 612, the user can separate the trial body 104 from the distalstem 202. Following the rotation of the separator instrument 102, andresulting decoupling of the trial body 104 and the distal stem 202, thetrial body 104 can be removed from the distal stem 202. In someexamples, the user can select another trial body 104 with differentparameters and repeat the method 600. The separator instrument 102 canbe removed from the insert 106 by rotating the separator instrument 102about its axis 130 in the opposite direction and pulling the one or morepins 112, 114 through the one or more slots 126, 128 away from the oneor more ramp elements 122, 124.

In the foregoing Detailed Description, it can be seen that variousfeatures are grouped together in a single example for the purpose ofstreamlining the disclosure. This method of disclosure is not to beinterpreted as reflecting an intention that the claimed examples requiremore features than are expressly recited in each claim. Rather, as thefollowing claims reflect, inventive subject matter lies in less than allfeatures of a single disclosed example. Thus the following claims arehereby incorporated into the Detailed Description, with each claimstanding on its own as a separate example.

Note that not all of the activities or elements described above in thegeneral description are required, that a portion of a specific activityor device may not be required, and that one or more further activitiesmay be performed, or elements included, in addition to those described.Still further, the order in which activities are listed are notnecessarily the order in which they are performed. Also, the conceptshave been described with reference to specific examples. However, one ofordinary skill in the art appreciates that various modifications andchanges can be made without departing from the scope of the presentdisclosure as set forth in the claims below. Accordingly, thespecification and figures are to be regarded in an illustrative ratherthan a restrictive sense, and all such modifications are intended to beincluded within the scope of the present disclosure.

Benefits, other advantages, and solutions to problems have beendescribed above with regard to specific examples. However, the benefits,advantages, solutions to problems, and any feature(s) that may cause anybenefit, advantage, or solution to occur or become more pronounced arenot to be construed as a critical, required, or essential feature of anyor all the claims. Moreover, the particular examples disclosed above areillustrative only, as the disclosed subject matter may be modified andpracticed in different but equivalent manners apparent to those skilledin the art having the benefit of the teachings herein. No limitationsare intended to the details of construction or design herein shown,other than as described in the claims below. It is therefore evidentthat the particular examples disclosed above may be altered or modifiedand all such variations are considered within the scope of the disclosedsubject matter. Accordingly, the protection sought herein is as setforth in the claims below.

What is claimed is:
 1. A trial system for determining a suitableproximal body implant for hip replacement surgery, comprising: aseparator instrument; a trial body attachable to a distal stem; and aninsert positioned within the trial body, the insert comprising: a firstramp element configured to receive the separator instrument such that asthe separator instrument is rotated about its axis, the first rampelement guides a first pin of the separator instrument so as to separatethe trial body from the distal stem.
 2. The trial system of claim 1,wherein a distal end of the separator instrument is configured tocontact a proximal end of the distal stem, such that the first rampelement facilitates separation forces between the distal end of theseparator instrument and the proximal end of the distal stem.
 3. Thetrial system of claim 1, wherein the insert is welded within the trialbody.
 4. The trial system of claim 1, wherein the insert is integralwith the trial body.
 5. The trial system of claims 1, wherein the distalstem comprises a distal stem trial.
 6. The trial system of any of claims1, wherein the first pin extends along an axis that is nonparallel tothe axis of the separator instrument.
 7. The trial system of any ofclaims 1, wherein the insert further comprises: a second ramp elementconfigured to guide a second pin of the separator instrument tofacilitate separating the trial body from the distal stem.
 8. The trialsystem of any of claims 1, wherein the trial body is attachable to thedistal stem via a taper lock.
 9. The trial system of any of claims 1,wherein the insert further comprises: a first slot configured to receivethe first pin and guide the first pin to the first ramp element.
 10. Thetrial system of any of claims 1, wherein the trial body is configured topass over a guide rod of the distal stem.
 11. The trial system of any ofclaims 1, wherein the insert comprises an interior passage that allowsthe separator instrument to pass through the insert.
 12. A trial systemfor determining a suitable proximal body implant for hip replacementsurgery, comprising: a separator instrument comprising a first pin; anda plurality of trial bodies, each trial body of the plurality of trialbodies comprising: a distal portion attachable to a distal stem; aproximal portion extending from and nonparallel to the distal portion;and an insert positioned within the distal portion of the trial body,the insert comprising: a first ramp element configured to engage thefirst pin of the separator instrument such that the first pin traversesthe first ramp element in response to rotation of the separatorinstrument about its axis, thereby allowing separation of the trial bodyfrom the distal stem.
 13. The trial system of claim 12, wherein theseparator instrument further comprises: a second pin extending from andnonparallel to the separator instrument.
 14. The trial system of claim13, wherein the insert further comprises: a second ramp elementconfigured to engage the second pin of the separator instrument suchthat the second pin traverses the ramp element in response to rotationof the separator instrument about its axis.